Expanding head for abrasives



O. S. DE HAVEN EXPANDING HEAD FOR ABRASIVES Filed July 26, 1946l APatented Dec. 16, 1947 yUNITED STATE EUANDING HEAD FOR ABRASIVES OliverS. De Haven, Beech Grove, Ind., assigner f to Vonnegut MoulderCorporation, Indianl apollo, Ind., a corporation Application July 2s,194e, semi No. sasso 4 claims. (ci. 51-191) 'This invention relates toan expanding head or wheel for receiving an endless band of abrasivevmaterial for grinding or polishing, wherein the abrasive is mountedabout the head for encirclementthereof when at rest and upon rapidrotation the head is caused to expand into gripping relation with thesurrounding abrasive under centrifugal force,

The object of this invention is to produce an expanding head. of simple,economical construction, such as will control the extent of itsexpansion in operation, the pressure applied to the abrasive band as aresult thereof, and the resiliency of its abrasive carrying surface sothat it may be adapted to different uses and purposes:

The invention4 is accomplished by forming the entire expanding head ofrubber having an inner core portion and an outer expanding portion whichmay be separated by an interposed annular breaker-strip or the bondingof rubber having different densities. By the relation of the coreportion and the expanding portion as to their respective diameters,various degrees of expanding characteristics, as well as varying degreesof yielding characteristics may be obtained to suit the desired purpose,as will be hereinafter more particularly set forth and described.

The full nature of the invention will be understood from theaccompanying drawings and the following description and claims:

Fig. 1 is a side elevation of an expanding head with an abrasive bandmounted thereabout.

Fig. 2 is an enlarged cross section taken on the line 2-2 of Fig. 1.

Fig. 3 is the same as Fig. l, showing a modified form -of expanding headwith the abrasive band removed;

Fig, 4 is an enlarged section taken on the line 4-4 of Fig. 3. A

Fig. 5 is the same as Fig'. 3, showing a further modification of theexpanding head.

Fig. 6 is an enlarged section taken on the line 6--6 of Fig. 5.

In Figs. 1 and 2 of the drawings there is illustrated an expanding headfor receiving an endless band of abrasive material indicated at 3. Therelative diameters of the band and the head are such that the abrasiveband may be readily placed about the head when at rest, and whereby thehead will expand outwardly into gripping and containing engagement withthe band under the action of centrifugal force when it is rapidlyrotated.

'I'he expanding head is formed of an inner and annular core III,preferably formed of dense or hard rubber and provided with a bore Ilfor receiving a driving spindle or shaft. The coreof dense or hardrubber is surrounded by a breaker strip I2 of non-elastic material suchas a woven "fabric, wire or the like and is suiiiciently strong toprevent any outward expansion of the core. Thus, the breaker strip isdesigned to confine the core within the prescribed limits. The core isvul'- canized to and within the breaker strip, said breaker strip beingsurrounded by the elastic expansible portion I3 of the head having aprescribed degree of stretch. The expansible portion I3 may be of denseor hard rubber, depending upon the purpose and use of the head. However,since it is not confined, and has a certain degree of stretch, theaction of the centrifugal force resulting from rapid rotation will causea stretching or expanding ofthe expansible portion I3 radially to engageand grip the surrounding abralsive band 9.

As it is desirable to control the expansible characteristics of thehead, the breaker strip I2 is located at a predetermined radial distancefrom the outer periphery of the expansible portion. The relativelocation of the breaker strip with respect to the periphery of the headdetermines its expansibility in conjunction with the character anddensity of therubber used. Thus, the breaker 4strip is designed to breakthe stretching relation ofthe head as between the inner core portion andthe outer expansible portion. Whereas in Figs. 1 and 2 the breaker stripis shown as being substantially closer to the bore of the core Ill thanto the outer periphery of the expansible portion I3, depending upon thepurpose and use, as well as the characteristics' of the rubber, it maybe located more nearly intermediate thereof or perhaps closer to theperipheral surface of the expansible portion.

In the modified form of Figs. 3 and 4, the core III) having the bore IIImay be of exceedingly hard or densev rubber to which the more resilientand expansible rubber portionV I I3 is vulcanized at II2. Thus, theradial thickness of the hard rubber with respect to the radial thicknessof the more resilient expansible rubber portion iI3 con- 'trols therexpansion of the head under centrifugal force. In this modication thevulcanized bond ||2 serves in a similar manner to the breaker lstripabove described, as defining and limiting the extent Vof its expansion.

In the modified form of the invention disclosed in Figs. 5 and 6, thereis provided an inner hard rubbercore 2in having a bore .2li confined by3 Y the breaker strip 2i2 in the manner and for the purpose abovedescribed in respect to Figs. 1 and 2. However, the expansible portion2l3 of the head may be of sponge rubber or a very light and flexiblematerial having a high degree of stretch and sufciently resilient toprovide an extremely soft cushion particularly adapted -for -polishing.Wherein the expansible portion 2|: has a high degree of stretch due toits density and characteristics, it may be desirable to support it by aninner rim 2 I4 of a dense or hard rubber. which in turn surrounds and isbonded to the breaker strip 2 i2. Thus, in this form, while` the breakerstrip serves in' its capacity to limit and, control the expansibilityo1' the expandible portion 2i3 in the .above described manner, the rim2M serves in a similar capacity to some degree -and further acts as astabilizing support for the light and less dense expansible portion 2i3.such as sponge rubber.

By reason of the above described structure an expansible head may beconveniently molded o! rubber or like material with the inner 'and outerportions thereof comprising material of the same radial distanceinwardly from the outer periphery of the head to limit the expansionthereof to the stretch of said body portion.

2. An expandinghead for abrasive bands comprising a core of denserubber, an annular outer expansible body portion of sponge rubber, aninner band of dense rubber bonded to said body portion, and a breakerstrip of non-elastic material interposed between and bonded to saidinner band and core respectively at a predetermined radial distanceinwardly from the outer periphery of the head to limit the expansionthereof to the stretch of said body portion and inner band.

' 3. An expanding head for abrasive bands comprising a core of denserubber, and an annular outer expansible body portion of rubber having adegree of stretch, said outer body portion sun rounding said core andbeing bonded thereto at a predetermined radial distance inwardly fromthe outer periphery of the head to limit the expansion thereof to thestretch of said body portion.

4. An expanding head forabrasive bands comprising an annular wheel ofrubber having a degree of stretch, and a breaker strip of non-elasticmaterial imbedded and banded within said wheel at a predetermined radialdistance from the outer periphery thereof for conning the inner portionthereof and limiting its expansibility to the outer portion.

OLIVER. S. DE HAVEN.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS

